Clinicopathological study of canine transmissible venereal tumour in leishmaniotic dogs

Introduction : Canine transmissible venereal tumour is occasionally observed in leishmaniotic dogs, and Leishmania amastigotes can be harboured in canine transmissible venereal tumour cells. Objectives : The aim of this paper was to investigate the clinicopathological significance of the association of both diseases. Methods : Nineteen dogs affected by canine transmissible venereal tumour and canine leishmaniasis were studied retrospectively. Results : In these dogs, the tumour manifested a large size and often aggressive behaviour (42%) and no predictive sign of spontaneous regression was observed. Sporadic Leishmania amastigotes were found within the canine transmissible venereal tumour in three cases, probably transported by infected macrophages often infiltrating the tumour. A high Leishmania parasitisation of canine transmissible venereal tumour was observed in two other cases and verified by immunohistochemistry. Clinical Significance : Canine transmissible venereal tumour is a tumour of the dog able to harbour a large number of Leishmania parasites. Alternatively, the systemic disease (canine leishmaniasis) may lower the immune defence against malignancy (canine transmissible venereal tumour).     

Urinary tract infection: The role of canine transmissible venereal tumour

The role of transmissible venereal tumours in the pathogenesis of urinary tract infection in dogs was investigated in 86 dogs. Fifty-five had transmissible venereal tumours, and the remaining 31 animals were used as controls. A thorough clinical examination of the external genitalia was carried out in each case. In the dogs with transmissible venereal tumours, the sites of attachment were recorded. Urine samples were taken by cystocentesis and the external genitalia swabbed; the samples were cultured for bacteria using standard methods. Tumours were found on the prepuce and other parts of the penis in male dogs; in bitches they were found in the vagina, vestibule or the vestibulovaginal junction. Dogs with transmissible venereal tumours were found to be at a high risk of having bacteriuria (odds ratio [OR] = 7.04). Obliteration of the urethral orifice by the tumour, possibly leading to urine retention, was thought to be the main reason for the high incidence of urinary tract infection among dogs with transmissible venereal tumours. Long-standing cases of transmissible venereal neoplasia had a higher chance of becoming bac-teriuric compared with recent cases (OR=29–60). This study indicates that transmissible venereal tumour may be a predisposing factor for the development of urinary tract infection.     

Role of exfoliative cytology in the diagnosis of canine transmissible venereal tumour

The objectives of this study were to evaluate the role of exfoliative cytology in the diagnosis of canine transmissible venereal tumour and to improve the success rate of surgical excision of this tumour. The technique was used to screen 360 dogs and, at the time of surgery, 34 clinical cases. Seventy-five per cent of the cases detected by screening were described as early stage disease in comparison with 23 per cent of cases reported by owners. The value of exfoliative cytology at the time of surgery to determine tumour cell removal was demonstrated by the reduction in local tumour recurrence from 22 per cent to 8 per cent. The technique is, therefore, recommended for use in screening dogs for canine transmissible venereal tumour and in determining the extent of surgical removal. However, more work is needed to assess its applicability in practice by determining its sensitivity, specificity and predictive values of a positive and negative test answer.     

Cytology of canine cutaneous round cell tumors. Mast cell tumor, histiocytoma, lymphosarcoma and transmissible venereal tumor.

Sixty-four canine cutaneous round cell tumors were divided into 25 mast cell tumors, 15 histiocytomas, nine cutaneous lymphosarcomas and 15 transmissible venereal tumors. The final diagnosis was made from cytologic, clinical and histologic findings. Cytologic features were significantly distinctive in mast cell tumor, transmissible venereal tumor, and most cases of histiocytoma and lymphosarcoma to allow a diagnostic opinion. This opinion was supported by subsequent histologic examination. In some instances cytology was considered essential in rendering a diagnostic opinion even though histology was available.     

Metastatic transmissible venereal tumour in dogs

This report presents six cases of canine transmissible venereal tumour (TVT) in the genital organs with metastasis to extragenital locations. These extragenital sites were the skin, lymph nodes, spleen, tonsils, liver and lung. Foci of metastasis were found in six different organs in one case, two organs in another case and one organ in the remaining four cases. Multiple tumour nodules were, however, found in certain organs such as the skin and spleen. The extragenital tumours were identified as TVT on the basis of their histological similarity to the primary genital tumours. Metastasis appeared to be mainly by lymphatic pathways and by oral implantation. Résumé. Ce rapport présente six cas de tumeur vénérienne transmissible (TVT) dans les organes génitaux avec métastase aux endroits extragénitaux. Ces endroits extragénitaux étaient la peau, les nouds lymphatiques, la rate, les amygdales, le foie et les poumons. Des foyers de métastase ont été trouvés dans six organes différents dans un cas, dans deux organes dans un autre cas et dans un organe dans les quatre cas restant. On a, cependant, trouvé des tumeurs multi-nodulaires dans certains organes tels que la peau et la rate. Les tumeurs extragénitales ont été identifiées comme TVT en se basant sur leur similarité histologique aux tumeurs génitales primaires. La métastase semblait ětre principalement par voies lymphatiques et par implantation orale. Zusammenfassung. Dieser Bericht stellt sechs Fǎlle dar von ùbertragbar venerischem Hunde-Tumor (TVT) in den Geschlechtsorganen mit Métastase an extragenitalen Stellen. Dièse extragenitalen Stellen waren die Haut, Lymphknoten, Milz, Mandeln, Leber und Lunge. Herden von Metastasen fand man in sechs verschiedenen Organen in einem Fall, zwei Organen in einem anderen Fall und in einem Organ in den ùbrigen vier Fǎllen. Zahlreiche Tumorknǒtchen (Noduli) wurden jedoch in gewissen Organen wie Haut und Milz gefunden. Die extragenitalen Tumoren waren als TVT identifiziert auf Grund ihrer histologischen ǎhnlichkeit mit den primaren Geschlechtstumoren. Metastasen traten hauptsàchlich durch lymphatische Bahnen und durch orale Einpflanzung ein.     

Evaluation of a genetic assay for canine transmissible venereal tumour diagnosis in Brazil

The canine transmissible venereal tumour (CTVT) is a transmissible cancer that is spread between dogs by the allogeneic transfer of living cancer cells. The infectious agents in CTVT are the living cancer cells themselves, which are transmitted between dogs during coitus. CTVT first arose several thousand years ago and the disease has a global distribution and is frequently observed in dogs from Brazil. We evaluated the utility of a LINE‐MYC quantitative polymerase chain reaction for diagnosis of CTVT cases in Brazil. Our analysis indicated that the LINE‐MYC rearrangement was detectable in all CTVT samples but not in their corresponding hosts. This genetic assay proves to be a useful tool for providing a definitive molecular diagnosis of CTVT, which presents with varying degrees of aggressiveness and invasiveness in different host dogs and can therefore be a diagnostic challenge in some specific cases.     

A retrospective evaluation of four surgical methods of treating canine transmissible venereal tumour

A total of 109 lesions were treated in a total of 109 dogs and bitches using simple surgical excision or diathermy, with or without the simultaneous removal of the gonads. Evaluation of the case, 49 months after surgery, showed that 35 (32.1 per cent) of the tumours had regressed completely whilst 74 (67.9 per cent) had recurred. Excision using diathermy was the more effective treatment irrespective of whether the gonads were removed. There was a significant difference in the frequency of recurrence and the time interval for it to recur (P < 0.05 and P < 0.25 respectively) when the methods of treatment were compared, however castration of either males or females had no significant effect upon the frequency of recurrence.     

Canine transmissible venereal tumour: a review

Canine transmissible venereal tumour (CTVT) is a contagious venereal tumour of dogs, commonly observed in dogs that are in close contact with one another, or in stray and wild dogs that exhibit unrestrained sexual activity. CTVT represents a unique, naturally transmissible, contagious tumour, where the mutated tumour cell itself is the causative agent and perpetuates as a parasitic allograft in the host. Clinical history, signalment and cytological features are often obvious for establishing a diagnosis though biopsy and histological examination may be needed in atypical cases. Most cases are curable with three intravenous injections of vincristine sulphate at weekly intervals. The role of stray and wild dogs makes the disease difficult to control and necessitates sustained animal birth control in stray dogs along with prompt therapy of the affected dogs. This review captures the manifold developments in different areas embracing this fascinating tumour, including its biology, diagnosis and therapeutic alternatives.     

Parvovirus-induced regression of canine transmissible venereal sarcoma

In 1981, during the worldwide canine parvovirus (PV) epizootic, canine transmissible venereal sarcomas growing in Beagles in a colony regressed earlier than expected after the dogs became infected with PV. Subsequent studies revealed that modified-live PV vaccine (feline panleukopenia virus) was capable of preventing tumor transplantation when the vaccine was inoculated simultaneously with the tumor in a site distant from the implantation site. However, the PV vaccine had no effect if it was inoculated 3 or 18 days after the tumor was transplanted.     

Heat shock proteins in canine transmissible venereal tumor

SDS-PAGE, Western blot analysis and immunohistochemical staining were used to detect heat shock proteins (HSPs) 60, 70 and 90 in canine transmissible venereal tumor (CTVT). Tissues tested for HSPs included: (1) tissues from different growth phases of CTVT tumors artificially induced in dogs; (2) tissues from other canine tumors; (3) normal dog tissues. Our results indicate that HSP 60 was consistently higher in CTVT cells in regressing phase than those in progressing phase. However, no detectable antibody response specific to the tested HSPs was found in the sera from CTVT-laden dogs in different growth phases. Although levels of the HSPs were all detectable in CTVT cells, only 60 and 70 were higher in CTVT cells than in normal tissues. In addition, none of the HSPs were detected in cells from five other canine tumors. These data suggest that canine HSP 60 and 70 are potential markers for CTVT and HSP 60 is appear to be involved in CTVT regression.PCR was used to confirm the existence of CTVT cells using primers designed to cover the sequence between the 5' end of c-myc near the first exon and the 3' end outside the LINE gene. Only CTVT samples were positive for this sequence; samples from other tumors and normal tissues were negative. The sequenced PCR products indicated that CTVT from Taiwan and other countries exhibited over 98% sequence homology. This reconfirms that, worldwide, all CTVT cells are very similar.     

A case of ocular canine transmissible venereal tumor

A 1-year-old, intact female mixed-breed dog was presented to St. George’s University Small Animal Clinic in Grenada for a third eyelid mass. The dog was diagnosed with a rare ocular transmissible venereal tumor (TVT) and concurrent anaplasmosis, ehrlichiosis and dirofilariasis. Treatment with vincristine sulfate resulted in complete resolution of the TVT.     

Metastasis of a transmissible venereal tumour to the pituitary

This report presents a case of metastasising transmissible venereal tumour (TVT) with lesions of the penis, lip, spleen and pituitary. The clinical picture is outlined and the associated diagnostic radiographic procedures used to reach a final diagnosis of a space–occupying lesion in the region of the pituitary are described. A definitive diagnosis of a metastasizing TVT was reached by histopathological examination and it is concluded that the pituitary and spleen metastases are examples of the systemic dissemination of the original penile tumour whilst the lip lesion probably arose by direct contact.     

Canine transmissible venereal tumour and ovarian papillary cystadeno-carcinoma in a bitch

A young German shepherd dog was presented for a protruding vaginal mass of one month's duration. Clinical appearance of the mass was suggestive of a canine transmissible venereal tumour. Diagnosis was confirmed by cytology; a single drug chemotherapy regimen using vincristine was instituted. Regression was evident within seven days after the first treatment. Bilateral ovarian papillary cystadenocarcinoma was an incidental finding after an elective ovariohysterectomy was performed.     

The distribution of C-bands in canine transmissible venereal tumor cells

Colchicine-arrested metaphase preparations, derived from canine transmissible venereal tumor (TVT) cells grown in culture, were characterized based on the occurrence and distribution of constitutive heterochromatin. Analysis of the data with regard to the distribution of C-bands in the pericentric, interstitial and telomeric segments revealed a nonrandom distribution along the arms of many chromosomes with the bulk of the bands occurring in the centromeric region. The frequency of C-banded regions differed from those reported for normal dog cells and both primary and transplanted tumors. These results suggest that similar nondifferentially-stained TVT karyotypes do not necessarily exhibit identical distribution of constitutive heterochromatin.